[Validation of the French version of the health-related quality of life questionnaire for adult strabismus (AS-20)].

INTRODUCTION

A growing number of articles have shown the negative impact of strabismus on self image, relationships with others and professional life. The AS-20 is a standardized questionnaire in English measuring the psychosocial impact of strabismus in adults. The goal of this study is to validate the AS-20 in the French language.

PARTICIPANTS

Three hundred and ninety one patients took part in the study: 131 had strabismus (group 1), 128 other ocular diseases (group 2) and 132 "normal" patients (group 3).

RESULTS

The AS-20 scale showed good psychometrical properties in 2 or 4 dimensions: internal consistency was very good (Cronbach's alpha coefficient>0.9 in all dimensions and overall) and the reproducibility was satisfactory (intra class coefficient>0.7). The comparison of the scores in the 2 dimension scale showed significant differences between the groups (P<0.001): lower score in strabismus (63.9±18.3) than in other ocular diseases (73.5±17.8) and normal group (89.4±12.0) (divergent validity). The 4 dimension psychometric analysis was performed by removing 2 items and grouping the 18 others in 4 groups. It confirmed the divergent and convergent validity, internal consistency and reproducibility of the scale. The results of the confirmatory factor analysis were better with the 4 dimension scale than the 2 dimension scale (adjustment coefficients>0.9).

CONCLUSION

We now have access to a health related questionnaire in French to quantify the impact of strabismus on quality of life and measure the results of treatment.